A method is provided for forming semiconductor copper seed layers with the copper alloyed with one of the metals from the group comprising tin, magnesium, and aluminum. The alloy further has a graded nitrogen content with the highest concentration of nitrogen proximate a tungsten nitride barrier layer....http://www.google.com/patents/US6368961?utm_source=gb-gplus-sharePatent US6368961 - Graded compound seed layers for semiconductors
